13 research outputs found
Microdevice for Sedimentation-based Separation of Blood Microsamples at the Point of Collection
No full textLaboratory blood testing plays a central role in current diagnostics and therapeutical decisions. Thus, errors have a direct impact on care quality and cost. The majority of errors occur in the pre-analytical phase, when samples are collected, stored and prepared. For biochemical analysis, the most common preparation operation is the separation of blood plasma: performing this operation upon sampling has the potential to simplify and render the testing cycle more reliable. Hence, in this work, a microdevice that performs blood separation at the point of collection is presented. The capillary-driven microdevice processes fingerprick blood microsamples without the need for external equipment. The device relies on sedimentation as a simple and spontaneous driving force for the separation of undiluted whole blood. Blood flows in the device at a velocity allowing cells to settle on the bottom of a constant height channel and create a higher viscosity liquid fraction. The supernatant plasma of lower viscosity is pumped at a higher speed than the sediment in the device. Thus, as the device fills, a plasma plug is generated in the downstream section of the channel. In this work, a unidimensional model of combining Kynch sedimentation and Poiseuille flow theories is established to describe this novel separation phenomenon. The impact of design and blood parameters on the separation is studied. The device can be used to separate fresh or anti-coagulated samples obtained through skin puncture. For both sample natures, the cell-free plug appears after a separation delay of 400 s. This delay is necessary to establish a sufficient viscosity contrast through sedimentation. Subsequently, for anti-coagulated samples, cellfree liquid is extracted with a 17 % yield. For fresh samples, coagulation leads to an increase of yield to 67 %. The combination of sedimentation and filtration through the clot are the reasons for this increase. Separated samples are retrieved from the chip through the use of an integrated ejection mechanism. The device is designed to eject a volume of 2ÎŒL of cell-free liquid out of 25ÎŒL of whole blood. The quality of separated samples was established by measuring particle contaminant concentration and proteomic profile. The contaminant concentration is lower and more repeatable than in centrifuged plasma or serum samples. In the protein profile, only 4.5% of quantified proteins show significantly different levels between serum and chip-separated samples - thus, showing that the separated samples and serum could be used interchangeably. The microdevice was combined with standard clinical automated analyzers to perform blood panels on 12 obese patients. Of the 8 blood markers analyzed, 7 markers showed significant correlation between the chip-separated and standard plasma samples. This shows that the microdevice can be used in combination with standard bench top analytical tools. The novel microdevice presented in this work paves the way to a family of microsystems that perform purely pre-analytical operations. The performance of the device, quality of retrieved samples and combinability with bench-top techniques indicate that the microdevice could impact on current testing cycles: the device could reduce the pre-analytical sources of errors by performing blood microsample separation at the point of collection.LMIS
Smart Knee Prosthesis for Orthopedic Surgery: the implantable and wearable Measurement System
Get PDFRecent advances in remote powering and telemetry permitted the use of sensors inside body. A few studies have been already done on smart knee prostheses, but all focused on monitoring the in-vivo contact forces and moments. A smart design, compatible with mechanical structure of commercially-available knee prostheses, that provides force and accurate kinematics feedback was suggested with all electronics housed in the polyethylene insert (PE). The current work addresses the designed kinematics and force measurement system of that smart implant and its validation in a robotic knee simulator.LMAMLMIS
Implantable and wearable measurement system for smart knee prosthesis
No full textIn this work we present the implantable and wearable measurement system developed for smart knee prostheses monitoring. The kinematic measurement system contains three anisotropic magnetoresistive sensors embedded into the polyethylene part of the prostheses. The kinematic measurement system also has two inertial measurement units to be worn by the subject on the shank and thigh. Each of this inertial measurement units consisted of a 3D accelerometer and a 3D gyroscope. The force measurement system contains implantable strain gauges that connected in two separate Wheatstone bridges and embedded in a designed capsule-like structure. These systems were validated in a robotic knee simulator against reference force and kinematics systems. The best angle estimator performed with an RMS error of 1.18°±0.25° over four different walking patterns, while the force sensors showed linear behavior in measuring the applied forces, where linear models obtained R2s larger than 0.98.LMAMLMIS
Observation device with optical compensation
No full textThe invention concerns an observation device such as cell culture wells comprising an optical element such as a lens or a filter, or even combinations thereof, for compensating an optical effect induced on a sample contained in the observation device and illuminated by a light beam traversing a meniscus. The interaction of a light beam with a meniscus interposed between said light beam and a sample to be visualized, alters the image readout of the sample so that the image thereof results negatively affected. By aligning the optical axis of the optical element with that of the meniscus, an optical effect such as non-uniform light distribution of illumination of the sample can be conveniently compensated. The invention further discloses the optical elements, characterising the observation device, per se.AVP-R-TTOLDC
Polyimide/SU-8 catheter-tip MEMS gauge pressure sensor
Get PDFThis paper describes the development of a polyimide/SU-8 catheter-tip MEMS gauge pressure sensor. Finite element analysis was used to investigate critical parameters, impacting on the device design and sensing characteristics. The sensing element of the device was fabricated by polyimide-based micromachining on a flexible membrane, using embedded thin-film metallic wires as piezoresistive elements. A chamber containing this flexible membrane was sealed using an adapted SU-8 bonding technique. The device was evaluated experimentally and its overall performance compared with a commercial silicon-based pressure sensor. Furthermore, the device use was demonstrated by measuring blood pressure and heart rate in viv
A pre-industrial magnetic cooling system for room temperature application
No full textIn this paper, a new type of reciprocating magnetic refrigerator working with high remanence permanent magnets as the source of the magnetic field is presented. The simulated and measured magnetic field at the machine air gap is about 1.45 T. Initially, gadolinium metal (Gd) was used as the magnetocaloric refrigerant. Its magnetocaloric performances and its quality were checked experimentally in a developed test bench. To attain high values of temperature difference between the hot and the cold sources (temperature span), a new design of the Active Magnetic Refrigeration (AMR) cycle was implemented. However, in order to reduce the energy consumption and then increase the thermodynamic performances of the magnetic system, a special configuration of the magnetocaloric materials is developed. The numerical results of the applied magnetic forces on the new configuration are given and analysed. The developed machine is designed to produce a cooling power between 80 and 100 W with a temperature span larger than 20 K. The obtained results demonstrate that magnetic cooling is a promising alternative to replace traditional systems
Traceable impedance-based single-cell pipetting, from a research set-up to a robust and fast automated robot: DispenCell-S1
No full textSingle-cell isolation is a truly transformative tool for the understanding of biological systems. It allows single-cell molecular analyses and considers the heterogeneity of cell populations, which is of particular relevance for the diagnosis and treatment of evolving diseases and for personalized medicine. Single-cell isolation is also a key process in cell line development, where it is used to obtain stable and high producing clonally-derived cell lines, thus contributing to the efficiency, safety and reproducible quality of the drug produced. High producing clonally-derived cell lines are however rare events and their identification is a time-consuming process that requires the screening of thousands of clones. Therefore, there is an unmet need for a device that would allow the fast and efficient isolation of single cells, while preserving their integrity and providing an insurance of their clonality.We proposed earlier an impedance based pipetting technology for isolation of single cells (Bonzon a al., 2020), with initial validations for state-of-the-art stem cell in-vitro and in-vivo assays (Muller a al., 2020). Here, we present the transition from this pioneering technology developed in an academic setting into an automated instrument, called DispenCell-S1, allowing for traceable isolation of single cells.We developed and validated models predicting the performances for 96-well plates single-cell isolation. This resulted in a time of dispense down to 3 min and a plate filling rate up to 96%. Finally, we obtained an impedance signal reliability for proof of single particle isolation of 99% with beads and ranging from 93 to 95% with CHO cells
Tip connector for fluidic and electrical connection
No full textA connector for providing both a fluidic and electrical connection is disclosed, said connector having a proximal end, a distal end and an elongated body in between, characterized in that the elongated body has an inner cavity spanning throughout its length, and the distal end comprises: a) an inner body portion comprising a first inner electrical contact and b) an outer body portion comprising a second outer electrical contact having a spring element. The connector is easily adaptable to many kind of fluidic actuators and particularly to pipette instruments usually found in laboratory practice and developed to adapt fluidic actuators and pipette instalments to work according to the Coulter principle in every working condition, in particular to adapt the electrical and fluidic connection between a sensing tip and an instrumented pipette.AVP-R-TTOLMIS4LDCSUPKINAlternative title(s) : (fr) Connecteur de pointe pour une connexion fluidique et électriqu
